Variable electrical apparatus.



O. F. ROTHEN.

VARIABLE ELECTRICAL APPARATUS.

APPLICATION FILED FEB. 25. 1915.

1,217,348. Patented Feb. 27,1917.

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0. F. ROTHEN.

VAR|ABLE ELECTRICAL APPARATUS.

APPLICATION FILED 511.25. 1915.

1,217,348. Patented Feb. 27,1917.

2 SHEETS-SHEET 2.

UNITE STATES PATENT @FFIQ OSCAR F. ROTHEN, OF WEEHAWKEN, NEV JERSEY, ASSIGNOR T0 FRITZ LOIVENSTEIN, 0F BROOKLYN, NEW YORK.

VARIABLE ELECTRICAL APPARATUS.

Application filed February 25, 1915;

To all whom it may concern:

Be it known that I, OsoAR F. Ro'rnnN, citizen of the United States, residing at vVeeh-awken, in the county of Hudson, in the State of New Jerse' have invented certain new and useful Improvements in Variable Electrical Apparatus; and I do hereby dec iare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to variable electrical apparatus; and it is concerned more particularly with variable self-inductances adapted for use in wireless apparatus such as radio signaling systems and the like for the purpose of adjusting the self-inductance of the circuits in. order to tune said circuits to certain desired periods of oscillation.-

The present invention deals especially with variable inductances wherein the variation is accomplished by movement of a contact element in continuous contact with the conductor of the inductance coil; the change being therefore by infinitesimal increments and hence smooth as opposed to variation by distinct steps. In attempting to provide apparatus of this character, difiiculty has heretofore been found in securing good contact between the moving and the fixed elements of the circuit, and in providing for easy manipulation of the moving elements without jerks. Inductance coils of the type known as flat or pancake coils are typical of inductance devices in which the foregoing difficulties have been encountered. The present invention provides means for varying the effective inductance of such coils in a smooth and continuous manner while avoiding the ditliculties above pointed out.

Broadly described, the invention consists in operatively associating a directing member with a movable contact element in such manner that the contact element may be caused to move in a predetermined spiral or helical path.

One form of apparatus which embodies the principles of the invention and which has been found especially satisfactory in practice is illustrated in the accompanying drawings, the example here given, however, be

Specification of Letters Patent.

Patented Feb. 27, 1917.

Serial No. 10,582.

ing merely typical of apparatus within the scope of the invention. In these drawings:

Figure 1 is a plan view of the apparatus with the operating handle removed;

Fig. 2 is a view in side elevation, partly in section;

Fig. 3' is an enlarged plan of the operating parts, partly broken away and in section on line 3-3 of Fig. 4;

Fig. a is a vertical section on the line 4 l of Fig. 3; and

Figs. 5 and 6 are plan views showing details of certain parts of the apparatus.

Referring to the drawings, the assembled apparatus is here shown as mounted on a block of wood or the like provided with holes 2 for the reception of tubes 3 made of suitable insulating material. In these tubes, round headed screws i are fastened, into the slots of which an edge of the flat band or ribbon conductor 5 is soldered. In the present example the screws 4 are so spaced and arranged on the tubes that the conductor when mounted thereon forms a spiral of uniform pitch.

In and of itself, the inductance coil constructed as just described is not my invention, and is merely typical of coils with which the novel mechanism now to be described is adapted to be employed in combination. In the form of my invention here shown and found most satisfactory in actual practice,- a member secured to and directing the movement ofthe contact element proper is arranged not only to be moved angularly by appropriate means, but also radially. As here shown, the contactor per se comprises contact springs 6 of suitable material, phosphor bronze in this instance, forming a clip adapted to fit over conductor 5 and to make continuous sliding engagement therewith. The clip is suitably secured as at 7 to a directing member or arm 8, which here consists of a rectangular copper rod on which is formed a rack 9. The contactor and its directing arm may conveniently be considered as together constituting a movable contactor device.

Mounted on the upper surface of the insulator block 1 is a plate 11 of insulating material to which is suitably secured in a central position a stationary pinion 12 and a metal washer 18, said washer being provided on its upper surface with an annular shoulder or raised portion 14. A. collar 15, here shown as a casting having an upper tubular portion slotted as at 15 to form a resilient clamping socket, receives an operating handie 16, screws 17 being provided to clamp the handle in place. In the under face of casting 15 is a recess 18 into which fits the annular shoulder 14 of the washer, the collar 15 being thus rotatable by means of the operating handle relatively to said washer and about the fixed pinion 12 as an axis, this being also substantially the axis of the spiral. The collar 15 is also provided on its lower surface with two transversely alined rectangular notches or recesses 19 adapted to accommodate slidably the bar or directing arm 8 and to maintain rack 9 in engagement with the pinion 12, while permitting and guiding longitudinal or radial movement of the directing arm through the collar as the bar is moved angularly. Spring 19 engages abutment l9 on the washer and presses with its arms against the rack 9, thus holding the slidable bar 8 in good electrical contact with the rear walls of the alined recesses 19 in the casting 15. A spring washer 20, in conjunction with scr w 21, yieldingly presses the collar or casting 15 axially toward plate or washer 13 and into substantial abutment therewith, and insures good electrical contact between bar 8 and said washer.

A lead 22 secured to plate 11 as by screws 23 extending through plate 11 and washer 13 is brought to a convenient terminal 2 1, which evidently represents electrically the movable contact element 6. One end 25 of the spiral conductor is connected by lead 26 to terminal 27, the terminals 24.- and 27 therefore affording means whereby he variable electrical. apparatus may be connected in any circuit where it is desired to employ the same.

In the apparatus here shown, the pitch circumference of the stationary pinion 12 is selected equal to the radial pitch of the spiral. By turning the handle or knob 16, the directing arm or bar 8 is moved not only angularly but is also moved radially to the extent of one pitch circumference of the stationary pinion for each complete revolution of the handle. The contactor 6 is therefore moved in such manner as to describe a spiral which coincides exactly with the spiral of the coil winding. It is clear that by this arrangement the contactor element may be moved along the spiral to any extent desired while continuously in contact with said conductor, thus enabling an operator to vary the effective inductance in a smooth and continuous manner by the most minute increments. The disadvantages due to variation in distinct steps or jerks are therefore obviated, while at the same time good contact of the cooperating moving parts is always insured.

While the specific embodiment of the invention shown in the drawings and above described is particularly advantageous for the purposes set forth, it is evident that in its broadest aspect the invention is not lim ited to such specific embodiment. Although of greatest present utility in connection with variable inductances, the i1 vention may be usefully applied to other electrical elements such as variable resistances, rheostats, etc.

What I claim is:

1. Variable electrical apparatus comprising the combination, with a spirally coiled conductor, and a movable contactor device adapted to make continuous contact with said conductor, of controlling means located centrally of said coil and provided with rack and pinion connection to said contactor device, whereby said controlling means is operable to compel combined angular and radial movement of said contactor device, such operation of said controlling means being effected without the aid of said coil.

2. Variable electrical apparatus comprising the combination, with a conductor in the form of a flat spiral coil and a movable contactor device adapted to make continuous contact with said conductor, of a controlling member provided with a transverse passage slidably accommodating a part of said contactor device and revoluble to effect angular movement of said device, provision being also made to compel substantially radial movement of said device in conjunction with such angular movement.

8. Variable electrical apparatus comprising the combination, with a conductor in the form of a flat spiral coil, and a movable contact device comprising a contactor element adapted to make continuous contact with said conductor and a directing arm operatively connected to said contactor element and provided with a rack, of a pinion stationarily mounted substantially in the coil axis, and an actuating member revoluble about said pinion, and arranged to slidably engage said directing arm while maintaining said rack in engagement with said pinion, the pitch circumference of said pinion being equal to the radial pitch of said spiral coil.

4.. Variable electrical apparatus comprising the combination, with a conductor arranged in a flat spiral, of a contactor adapted to move along said conductor in continuous contact therewith, a directing arm associated with said contactor and movable both angularly and longitudinally, revoluble means located centrally of said spiral and operable to produce angular movement of said arm, and means for producing longitudinal movement of said arm in conjunction with such angular movement.

5. Variable electrical apparatus comprising the combination, with a spirally coiled conductor and a contactor movable therealong, of a directing arm movable to shift the contactor along said conductor, means slidably engaging said directing arm and revoluble to move the same angularly, and mechanism arranged to move said directing arm longitudinally in conjunction with the angular movement.

6. Variable electrical apparatus comprising the combination, with a conductor in the form of a fiat spiral coil and a contactor movable along said conductor while in contact therewith, of a directing arm supporting said contactor, and means operable to compel combined angular and longitudinal movement of said contactor, such operation of said means being eiiected without the aid of said coil, and leads electrically connected, respectively, to a point on said coil and to said movable contactor.

7. Mechanism for use with variable elec trical elements comprising a contactor, a dire'cting arm therefor, and means operable to impart combined angular and longitudinal movement to said arm in one plane, whereby said contactor may be compelled to travel in a plane spiral path.

8. Mechanism for use with variable electrical elements comprising a movable contactor, a directing arm for moving the same, in combination with means revoluble to im part angular movement to said arm, provision being also made for compelling longitudinal movement of said arm, both angular and longitudinal movements of said arm being restricted to one plane.

9. Mechanism for use with variable electrical elements comprising a contactor, and a directing arm for moving the contactor, said arm being provided with a rack, a mem ber slidably engaging said arm and revoluble to move said arm angular-1y, and a pinion mounted to engage said rack and arranged to move said arm longitudinally when the arm is moved angularly.

10. Mechanism for use with variable electrical elements comprising the combination, with a suitable base, of a pinion stationarily supported thereby, a member revoluble about said pinion, and a contactor device provided with a rack, said member slidably engaging said contactor device and maintaining said rack in engagement with said pinion.

11. Variable electrical apparatus comprising the combination with a conductor arranged in a spiral, of a stationary pinion mounted substantially in the axis of the spiral and having a pitch circumference substantially equal to the pitch of the spiral, a contactor device provided with a rack and adapted to make electrical contact with said spiral, and means for moving said contactor device angularly while maintaining its rack in engagement with said pinion.

12. Variable electrical apparatus com prising the combination, with a conductor in the form of a flat spiral coil, of a contactor adapted to be moved along said conductor, a directing arm supporting said contactor, and means operable to impart combined angular and substantially radial movement to said arm.

In testimony whereof I hereunto afiix my signature in the presence of two witnesses.

OSCAR F. ROTHEN.

Witnesses:

' ALFRED S. KUHN,

S. KAPLAN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

